An interesting article popped up a few days ago in which John Dagy, a journalist with Sportscar365, was discussing the TCR class of cars with John Doonan, the head of Mazda Motorsports program.
I have been following the TCR series for a while now with some interest in it as the car Mazda offers that fits best is the Mazda 3, and I enjoy the time I have had racing CorkSport’s Gen3 Mazda 3.
What is nice about the series is that it is meant to race four-door saloons, all with a 2.0 turbo motor and a price-capped ceiling of 135,000. Most people would freak out a bit with that price but what you are getting is a fully developed car with a spec sheet. Each manufacturer designates a builder, whether themselves or a shop, to assemble the cars and provide support.
Mazda is in an interesting spot; they have their successful Global MX5 cup series and the IMSA Prototypes with Joest, but there is a middle-ground hole that has been filled with the older NC Miatas. With the NCs not being a current production model, it makes sense to get something in there to fill in the blanks.
In the past, Mazda had used the Mazdaspeed 3 as the basis, and it did well capturing the championships in PWC and IMSA ST class, but the lack of a turbo model makes this a challenge.
Many have tried, but few have succeeded to retrofit or modify an existing throttle body to work with the Mazdaspeed DISI MZR platform.
As you know, CorkSport does things a little differently, and as a result, we started from the ground up to create the best performance throttle body possible with no sacrifices to drivability or reliability. Introducing the CorkSport 72mm Throttle Body for 2007-2013 Mazdaspeed 3, 2006-2007 Mazdaspeed 6, and 2007-2012 Mazda CX-7.
Starting from the ground up means 100% brand new parts, no reworked or refurbished components anywhere.
We start with an aluminum investment cast body that is made to our specific design specifications.
A flat faced throttle plate is added to gain a little bit of extra flow by avoiding the bump of a traditional round pivot shaft.
Finally, new electronics are added that are based upon OE logic to avoid any tuning and calibration issues.
To retain easy installation, we knew we had to keep the OE bolt pattern. With this, we wanted to maximize the throttle plate diameter for maximum flow. We ended up increasing from 60mm to 72mm. This may not sound like a huge increase, but the OE Throttle Body fits inside the CorkSport Throttle Body with plenty of room! The 72mm size also fits well with both 3” and 2.5” intercooler piping to fit almost any TMIC or FMIC setup. Finally, we did away with the OE gasket (which is too small anyway) and replaced it with a durable O-ring that will hold up to oil, gasoline, methanol, and other fueling options that it may come in contact with.
The CorkSport Throttle Body underwent extensive testing to ensure that it will not fail during daily use and to ensure it performs as well as we expect. The throttle plate underwent endurance testing to validate the D-shaped pivot can stand the test of time. During flow bench testing, we found that the CS flows about 150CFM (~33%) better than the OE throttle body when 75% open (accelerator pedal fully depressed).
Check out the graph below for the full data.
In daily driving testing, we noticed better throttle response with no CEL or choppiness. In power testing with a midsized turbo (~GT30 size) we found the throttle body caused faster spool, but when we moved to a big turbo, things got interesting. With a GT35R, the CorkSport Throttle Body caused 100-200RPM faster spooling and an increase in power. Check out the dyno graph down below to see the difference between the CS Throttle body (blue) and the OE throttle body (green).
Each throttle body ships with fresh stainless steel mounting hardware, a 3” stainless t-bolt clamp, and your choice of silicone. We have options for FMIC, Mazdaspeed 3 TMIC (which also works for you CX-7 guys), and Mazdaspeed 6 TMIC.
If you’re looking to take your Mazdaspeed3, Mazdaspeed6, or CX-7 to the next level, or squeeze that last bit of power out of your big turbo build, the CorkSport Throttle Body can help you meet your goals.
CorkSport is happy to announce the release of our long awaited 2010-2013 Mazdaspeed 3 Exhaust Mid Pipe. Designed by our engineers to be a simple, bolt on upgrade for your Mazdaspeed 3. The CorkSport mid pipe changes the exhaust note only slightly and gives a pleasant tone unlike some Mazdaspeed exhausts on the market which can sound hollow and buzzy. The exhaust features 80mm piping and a single resonator, all constructed from T304 Stainless Steel.
As with all of our CorkSport exhaust components, the Mazdaspeed 3 mid pipe features mandrel bent, polished stainless steel T304 construction for corrosion resistance and a clean stylish look. It has a distinctive performance sound that is mild but noticeable at cruise and idle but packs a bit more of a rumble when you’re really getting on the throttle.
After multiple years of testing, design and research, CorkSport is proud to announce its release of camshafts specifically designed around the MZR DISI platform. This kit is engineered to reliably provide increased power and torque without lower rpm sacrifices.
The turbocharged MZR DISI engine was first introduced in the 2006-2007 Mazdaspeed6 and was later put in the 2007-2013 Mazdaspeed3. This engine has a High-Pressure Fuel Pump (HPFP) that is driven off the intake camshaft. Other MZR engines use different camshafts and don’t have a HPFP lobe to run the fuel pump. This has been a limitation in the market since the engines introduction.
Camshaft Basics
In order to understand the basics you need to know some camshaft terminology. The most common terms are lobe, lift, duration and base circle.
Common Drawing of Camshaft Terminology
Base Circle – The circle on the backside of the lobe. When the base circle faces the valve the valve is closed.
Lobe – The lobe is the portion of the camshaft surface that is not the base circle. This is when the valve is opening or closing.
Lift – The distance between the base circle and the top of the lobe. This will be the amount the valve is allowed to open.
Duration – The distance, in degrees, that the camshaft is in the lift section. This controls the time that the valve will be open. This is shown in the diagram from A to B.
MZR Flow Testing
The first thing to do was flow test the head to figure out where restrictions might occur. To flow test, a constant vacuum was applied through the head and while slowly opening the valves. This is similar to what the engine is doing while running.
Intake lift
The factory intake ports do not flow much air above 0.350” of lift on the flow bench. The factory camshaft runs rough at 0.370” of lift. Shown in the graph below, minimal flow was increased between 0.350” and 0.400” on the factory head.
Intake Ports of MZR DISI Head
Porting is the process of modifying the intake and exhaust ports of an internal combustion engine to improve the quality and quantity of the air flow. After porting the head, there were significant increases in flow, but around 0.400” of lift there was again minimal increase in flow, with more lift. Testing suggests a proper maximum lift of 0.390” for the intake camshaft. Factory heads or ones with a large port should show gains from this increase in lift.
Why Stop at 0.390”?
More lift above 0.390” would require very extensive head work to gain much more power. Another downside of going above 0.390” lift is the valves will require stronger valve springs to maintain proper valve operation at high boost or high rpm. Upgraded valve springs should not be required for a factory head with 0.390” of lift camshafts.
Exhaust lift
A similar process to that described during the intake lift process was used on the exhaust ports and an optimal lift of 0.355” was chosen. For comparison, the factory runs 0.321” lift on the camshaft.
Exhaust Ports of MZR DISI Head
Limitations of Existing Options
The factory camshafts were designed around a compromise of performance and emissions; from that design criteria, there is still more power and torque available. The reader can now understand why increased lift and duration can release this power. There are limited options to increase lift and duration on the MZR DISI engine.
Reground Factory Camshafts
In order to increase lift and duration on a reground camshaft, the factory camshaft must be welded and reground to the new profile, but commonly the base circle is reduced. This allows the lift to increase and also the duration to be adjusted.
There are limitations with this approach. When reducing the base circle, many other parts in the head will have to make up for the amount ground away. It is essentially limited to the amount ground away. It is also limited by the duration because the profile must fit within the factory profile design.
In order to regrind a camshaft it must be removed from the engine or a new camshaft must be bought. A used camshaft can have wear that cannot be fixed. Buying new camshafts to send out is expensive and adds to the total cost of installing the camshafts.
Aftermarket Camshafts
The only aftermarket camshafts currently available are not designed for the MZR DISI engine. This means the intake camshaft does not have the ability to run the HPFP.
The existing camshafts for the MZR engine were also designed around naturally aspirated (non-turbocharged) engines, so the duration, lift, and overlap between the intake and exhaust camshafts are not optimal for forced induction applications.
The best option to upgrade camshafts is to buy those designed and made for the MZR DISI engine specifically.
Camshaft Design
In order to start testing camshafts on the car, a blank camshaft is needed. This requires making a mold and casting a generic camshaft from a mold. Then the bearing services were machined to factory specs and after that a few dozen durations, ramp rates, and overlaps based on the engines natural pumping ability were chosen.
Blank Camshaft with Bearing Surfaces Ground
After carefully grinding all of the blanks, it was time to dyno the engine and determine the difference in power and torque.
An engine is basically a vacuum pump with the camshaft helping determine at what rpm the pump is efficient. Camshafts allow the power under the curve to be manipulated. If you have ever taken a calculus or thermodynamics class you might have flashbacks.
Power/Torque Factory Camshaft vs CorkSport Camshaft
Potential variations in the engine tune, fuel, outside temperature, and other factors were monitored. The result is clear improvements in power and torque throughout the rpm range. The final design was chosen to limit lower rpm power decrease with a large band of power improvement over 4,500 rpm.
Exhaust Camshaft Comparison
Further examination of the exhaust lobe design is a good example of where the power comes from. When looking at the lift versus degrees as the cam spins, the changes to the lobe profile become apparent.
Exhaust Camshaft Design
This change allows the camshaft to lift the valve more and longer. This allows more air to flow out of the engine.
Intake and Exhaust Relationship
The intake camshaft is electronically controlled. With additional tuning, turbo spool and power can be increased by controlling the overlap between the intake and exhaust camshafts. Overlap is the time when both intake and exhaust are open at the same time. Typically in a turbo car overlap is much smaller than in naturally aspirated cars. Below shows intake and exhaust camshafts placed over each other and the area that would be considered overlap.
Diagram of Overlap
Fuel Pump Lobe
Recall the intake camshaft drives the mechanical HPFP. In order to allow the end user to have the best camshaft possible and also have reliable fueling and limited wear the fuel pump lobe on the CorkSport intake camshaft is ground to match the factory camshaft lobe and then rechecked to ensure no clearance issues.
Installation:
The installation of camshafts in the Mazda MZR engine is not easy. Camshaft upgrades should be considered by an experienced enthusiast or professional installation is appropriate. To aid an experienced installer, detailed installation instructions are provided. Successful installation is supported in two different ways.
Whether you want a lower center of gravity for better handling or you want to get rid of that ugly wheel well gap, lowering springs are a great buy.
From hitting the track on the weekend to a spirited drive through the countryside, CorkSport lowering springs are the upgrade you’ve been looking for. By adding our lowering springs, you’re lowering the center of gravity. This allows the car to stay more planted to the road.
One of the biggest things to note on the stock suspension is how far upward the suspension travels when hitting bump. It can make the car feel like it wants to lift off of the road depending on how fast you’re taking corners. Lowering springs help correct the car’s suspension travel when you hit a bump in a turn.
Lowering springs also have about 25% increased stiffness. For the Mazdaspeed platform, increased stiffness in the rear is a must. Mazdaspeeds like to squat pretty hard when hitting full boost, so any way you can manage to stiffen up the rear is a great modification for your car.
Adding lowering springs also gives your baby amazing eye appeal and a much more aggressive look. Whether you drive a MS3, MS6, Mazda 3, or MX-5, lowering springs will get rid of that ugly wheel well gap. If your model wasn’t just mentioned, springs will still work for you too! The result is a Mazda that carries a much cleaner look and gives you the ability to take it to the track if you want to.
Some people want to drop their Mazda as much as possible, and some don’t. CorkSport lowering springs don’t deliver a super aggressive drop. If you’re not interested in scraping your front bumper on every road bump, the CorkSport lowering springs have the right drop for you, and provide the increased handling capabilities you’re looking for.
Everything A Noob Should Know About Mazda Lowering Springs July 2nd, 2020CorkSport
